1. Field of the Invention
The present invention relates to an apparatus for supplying a source and an apparatus for depositing a thin film having the same, and more particularly, to an apparatus for supplying a source, which can quantitatively supply a powder source that is a deposition material, and an apparatus for depositing a thin film having the same.
2. Description of the Related Art
In general, methods for forming a thin film are classified into physical vapor deposition (PVD) methods, such as a sputtering method for forming a thin film using physical bombardment, and chemical vapor deposition (CVD) methods for forming a thin film using chemical reaction.
In the CVD method, a thin film is generally deposited using a reaction source in a gas state. However, when it is difficult to prepare a reaction source in a gas state since heavy elements with large atomic weight are contained in a reaction source, a thin film is deposited using a source gas evaporated after evaporating a powder source in a solid state. For example, in an organic light emitting diode (OLED), an organic thin film which functions as a light emitting layer is deposited using a powder source in a solid state. Therefore, an apparatus for depositing an organic thin film using a CVD method is generally provided with at least one apparatus for supplying a source, which supplies a powder source stored in an additional canister into a chamber.
Meanwhile, in a general apparatus for supplying a source, a powder source stored in a canister is supplied into a chamber by a method using a pressure difference or a method using a screw thread. First, in the method using a pressure difference, a pressure difference is generated between a canister and a chamber by injecting a first gas into the canister, and a powder source is then discharged to the outside of the canister due to the pressure difference and supplied into the chamber. Accordingly, the supply amount of the powder source is controlled by the injection pressure of the first gas. However, such a method has a problem in that the supply amount of the powder source is frequently changed due to the influence of the amount and kind of the powder source remaining in the canister, moisture, static electricity and the like. On the other hand, in the method using a screw thread, a rotary shaft having a screw thread is installed in a canister and is rotated, and a powder source is supplied into a chamber by allowing the powder source to be discharged to the outside of the canister along the screw thread by the rotation of the rotary shaft. Accordingly, the supply amount of a powder source is controlled by the pitch and rotational speed of the screw thread. However, this method has a problem in that if particles of the powder source are fine, the powder source is stuck between the screw thread and an inner wall of the canister so that the powder source cannot be supplied into the chamber. Thus, it is not suitable for supplying a very small amount of a powder source into the chamber, and the supply amount of a powder source also varies every time.
As described above, in conventional apparatuses for depositing an organic thin film, it is difficult to quantitatively supply a source that is a deposition material, and it is more difficult to supply a very small amount of the source correctly. Thus, it is difficult to control the thickness of a thin film to be uniform, and the quality of the thin film is degraded, thereby making it difficult to stably perform a thin film deposition process.